| a migratory baleen whale, Balaenoptera musculus, mostly of oceans and seas in the Southern Hemisphere, growing to a length of 100 ft. (30.5 m) and having a furrowed, slate-blue skin mottled with lighter spots, in some seas acquiring a yellowish coating of diatoms on the underside: the largest mammal ever known, it is now endangered. |
blue whale  (click for larger image in new window) n. A very large whalebone whale (Balaenoptera musculus) having a bluish-gray back, yellow underparts, and several ventral throat grooves. It is considered the largest living animal, sometimes reaching a length of 30.5 meters (100 feet). Also called sulphur-bottom. |
